Ok, i thought this was just a lightining issue, but there's clearly a lot more wrong here.
In the original notice how Cloud moves his eyes, how be blinks, there are even very subtle lip movements. In this demo his face is completly static, like a clay doll.
There IS one explanation for it though (a very light spoilery one), and that is they're using a different character model for this Cloud because this is a flashback from the past, thus he should look younger. Then they cut corners with this specific model since it wouldn't be used a lot.